Using a rotary device for treating molten metal

• US 4,673,434 A
• Filed: 08/04/1986
• Issued: 06/16/1987
• Est. Priority Date: 11/12/1985
• Status: Expired due to Fees

• Current Assignee: Foseco International Limited (Vesuvius Plc)
• Original Assignee: Foseco International Limited (Vesuvius Plc)
• Inventors: Withers, Christopher J., Pattle, David W.
• Primary Examiner(s): Rosenberg, Peter D.
• Application Number:
  US06/892,813
• Time in Patent Office: 316 Days
• Field of Search: 75/61, 75/67, 75/93 R
• US Class Current: 75/708
• CPC Class Codes: C22B 21/064 using inert or reactive gases C22B21/066 and C22B21/068 take precedence
• CPC Class Codes: C22B 9/05 Refining by treating with gases, e.g. gas flushing also refining by means of a material generating gas in situ
• CPC Class Codes: F27D 3/16 Introducing a fluid jet or current into the charge porous elements for gas flushing of molten metals B22D1/005

Abstract

A rotary device for dispersing a gas in molten metal, for example argon in molten aluminium, contained in a vessel, comprises a hollow shaft and a hollow rotor fixedly attached to the shaft, the rotor having a plurality of vanes each extending from the shaft, or a location adjacent the shaft, towards the periphery of the rotor whereby the hollow interior of the rotor is divided into a plurality of compartments, at least one aperture in the top or bottom of the rotor adjacent the shaft and at least one aperture in the peripheral surface of the rotor such that when the rotor rotates molten metal can enter each of the compartments through the aperture or apertures in the top or bottom, and flow outwardly through the peripheral aperture or apertures and at least one duct for the passage of the gas extending from the hollow interior of the shaft to each of said compartments. The gas and molten metal are mixed together within the rotor and on emerging from the rotor the gas is dispersed throughout the body of the molten metal as a stream of very small bubbles.

Claims

1. A method for the treatment of molten metal utilizing a rotary device comprising a hollow shaft and a hollow rotor affixedly attached to the shaft, the rotor comprising top, bottom and peripheral surfaces and a hollow interior and said rotor having a plurality of vanes each extending from the shaft towards the peripheral surface of the rotor so that the hollow interior of the rotor is divided into a plurality of compartments, with at least one aperture in at least one of the top and bottom surfaces of the rotor adjacent the shaft and at least one aperture in the peripheral surface of the rotor, and at least one duct for the passage of gas from the hollow interior of the shaft to each of the compartments, the method comprising the steps of:

dispersing a gas in molten metal contained in a vessel by rotating the shaft so that the molten metal enters each of the compartments through the at least one aperture in the at least one of the top and bottom surfaces, and flows outwardly through the at least one aperture in the peripheral surface, supplying gas to the at least one duct, and passing the gas from the hollow interior of the shaft to each of the compartments to be dispersed in molten metal within the compartments.

2. A method as recited in claim 1 wherein the gas is a gas for treatment of the molten metal, and wherein said dispersing step is practiced by rotating the rotatable shaft within the range of about 280-400 rpm, and by providing a gas flow rate within the range of about 20-35 normal liters/minute.

3. A method as recited in claim 1 wherein the rotor has one or more apertures in both its top and its bottom, and wherein said dispersing step is practiced so that the molten metal flows outwardly through the apertures in both the top and bottom surfaces of the rotor.

4. A method as recited in claim 1 wherein the vessel comprises a ladle, and comprising the further step of, after dispersion of the gas in the molten metal, pouring the molten metal out of the ladle.

5. A method as recited in claim 1 wherein the vessel comprises an inlet channel, a treatment chamber, and an outlet channel, and comprising the further step of filtering the molten metal in the outlet channel.

6. A method as recited in claim 1 wherein the vessel contains one or more immersion heaters, and comprising the further step of heating the molten metal with the immersion heaters during the practice of the dispersing step.